Browsing by Subject "Degraded task"

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    An fMRI investigation of perceptual impairments on the DS-CPT in Schizophrenia patients.
    (2010-12) Force, Rachel Brook
    The Degraded-Stimulus Continuous Performance Task (DS-CPT) has been utilized to examine vigilance deficits in schizophrenia patients for decades. However, recent evidence suggests sustained attention may not be the foremost cognitive process underlying task performance. Through the use of functional magnetic resonance imaging (fMRI) and manipulating the perceptual load of the objects in a pseudorandomized order regions of interest that are involved in the creation and maintenance of novel mental representations as well as the implementation of unambiguous cues were identified. Whole-brain exploratory analysis resulted in statistical regions of interest that were further categorized as to their response patterns as involved in task performance, task difficulty, object perception, and the default mode network. Group differences were found in each category of response and correlations with behavioral indices indicated several mechanisms that may underlie cognitive deficits. As areas identified as providing top-down feedback such the dorsolateral prefrontal cortex, anterior cingulate cortex, and orbitofrontal cortex exhibited atypical activation, functional compensatory mechanisms may contribute to the lack of performance deficits observed in this sample. Increasing the understanding of the brain mechanisms involved in DS-CPT performance in schizophrenia patients may offer greater insight into the nature of visual perceptual deficits in the disorder.